(13) Support the face of valve chest (40)
(15), and piston (18) from con-
that bears against motor case (43),
necting rod (34).
and press rotary valve bushing (41)
Note. Do not attempt to drive the wrist
out of the valve chest using a suitable
pin out. It will be easily removable with
Caution: Be careful not to shear
Remove piston ring (16) and oil
off bushing key (42). Make sure that
regulating ring (17) from piston
the arbor clears the key during re-
Repeat the above procedure until all
Pull the entire crank (26 through 39)
out of motor case (43). If necessary,
Clean all parts with an approved solvent,
tap the face of the motor case with a
and blow dry with compressed air.
mallet to free ball bearing (39) from
6-82. Inspection and Repair
Note. If the crank parts cannot be re-
a. Inspect all parts for wear and damage. Re-
moved, first remove rotary valve (24) as
fer to table 4-l for permissible wear measure-
described in steps 10 and 11. Then insert
a hardwood arbor through rotary valve
b. Inspect all hardware for damaged
bushing (41), and drive out the crank.
threads. Retap or rechase threads if stripped
Remove cotter pin (27) and castel-
or crossed, or replace if unserviceable.
lated nut (28). Drive out crank lock
brake piston (27), brake cylinder (37) drive
Separate valve end crank (30) from
shaft (42), and gear housing (53) for cracks,
pin end crank (37).
nicks, and burrs on machined surfaces, and for
Note. These parts are matched and
stripped or crossed threads. Remove nicks and
must not be replaced individually.
burrs with a fine file or handstone, and retap
or rechase all damaged threads. Replace if un-
Remove connecting rod rings (33),
connecting rods (34), connecting rod
d. Inspect all bearings for
bushing (32) and crank pin sleeve
and wear. Replace if unserviceable.
e. Inspect motor pinion gear spacer (11)
for scoring marks and wear. Replace if dam-
(26 and 39), use a suitable bearing
puller to remove them from the crank.
f. Inspect all gears and pinions for
Remove valve chest cover (21).
chipped teeth, damaged bores, and excessive
Screw a 1 l/&inch threaded bolt in-
wear. Replace if in doubt as to the service-
to the tapped hole in the exposed
ability of a part.
rotary valve (24). Pull the bolt to re-
g. Inspect brake band assembly (39) for
move the rotary valve.
wear and damage. Replace if unserviceable.
Note. Do not remove valve chest (40)
unless necessary to replace rotary valve
a. Propelling Air Motor. Reassemble pro-
pelling air motor in reverse of numerical se-
To remove valve chest (40) screw
two 5/8-11 threaded bolts (at least
following special procedures:
4 inches long) into the tapped holes
of the valve chest. Turn in the bolts
(plain end first) over pin end crank
evenly until they hear against motor
case (43) to free the valve chest.